نتایج جستجو برای: sulfur
تعداد نتایج: 32690 فیلتر نتایج به سال:
The Gomori-positive glia are periventricular astrocytes with abundant cytoplasmic granular material, predominantly occupying a periventricular site in the brain. These granular inclusions are strongly stained with chrome hematoxylin in the Gomori's method as well as exhibit red autofluorescence and non-enzymatic peroxidase activity. The glial Gomori-positive material (GGPM) granules are positiv...
Sulfur-utilizing autotrophic denitrification relies on an inorganic carbon source to reduce the nitrate by producing sulfuric acid as an end product and can be used for the treatment of wastewaters containing high levels of nitrates. In this study, sulfur-denitrifying bacteria were used in anoxic batch tests with sulfur as the electron donor and nitrate as the electron acceptor. Various medium ...
Sulfur atoms are present as thiol and thioether functional groups in amino acids, coenzymes, cofactors, and various products of secondary metabolic pathways. The biosynthetic pathways for several sulfur-containing biomolecules require the substitution of sulfur for hydrogen at unreactive aliphatic or electron-rich aromatic carbon atoms. Examples discussed in this review include biotin, lipoic a...
Mutation of a serine that forms a hydrogen bond to the iron-sulfur cluster of the Rieske iron-sulfur protein to a cysteine results in a respiratory-deficient yeast strain due to formation of iron-sulfur protein lacking the iron-sulfur cluster. The Rieske apoprotein lacking the iron-sulfur cluster is inserted into both monomers of the dimeric cytochrome bc(1) complex and processed to mature size...
The crystal structure of the bovine Rieske iron-sulfur protein indicates a sulfur atom (S-1) of the iron-sulfur cluster and the sulfur atom (Sgamma) of a cysteine residue that coordinates one of the iron atoms form hydrogen bonds with the hydroxyl groups of Ser-163 and Tyr-165, respectively. We have altered the equivalent Ser-183 and Tyr-185 in the Saccharomyces cerevisiae Rieske iron-sulfur pr...
One hundred fifty-six biogenic calcites and 96 whole rock carbonate samples of Paleozoic and Mesozoic age have been analysed for their sulfur isotopic composition. Recorded in structurally substituted sulfate (SSS) in the calcite lattice, the sulfur isotopic composition is thought to reflect the sulfur isotope value of ambient seawater sulfate. Possible alterations of the signal have been asses...
The uptake of hydrogen sulfide by carbon materials (ACFs and BPL) under dry and anoxic conditions was tested using a fixed bed reactor system to determine the effects of sorbent properties, temperature (200–800 C) and sulfurization protocols on the sulfur content, sulfur stability, sulfur distribution, and to elucidate possible reaction mechanisms for the formation of sulfur species. Sorbents w...
Hydrophilic sulfur sols prepared from sodium thiosulfate and concentrated sulfuric acid and purified by repeated NaCl precipitation and peptization in water have been studied by chemical analysis, vibrational spectroscopy, ion-pair chromatography and reversed-phase HPLC. The composition of the sol is Na1 6 4S2 8 .606 • 5.9In S„ • 1.0 NaCl. The elemental sulfur S„ (n = 6 1 4 ; mainly S8) account...
This report presents the chemical and physical factors governing the generation of sulfur dioxide (SO2), its transformation into other sulfur compounds, and the removal of sulfur oxides within the cement kiln system. Sulfur in cement kilns is derived from both kiln feed and from the kiln fuel. The form of the sulfur dictates the location in the kiln where the SO2 generation takes place. Sulfur ...
The use of recoverable sulfur particles will enhance the feasibility and reduce the cost of bioleaching process. Three different forms of sulfur particles, powder, pastilles and pellets were used to study the utilization and recovery of sulfur, used as energy source for thiobacilli in the bioleaching process. The Langmuir isotherm was used to explain the adsorption equilibrium existing between ...
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